sh4: review of regexp-macro-assembler-sh4.h

Changes:
- updated comments
- no fix
sh4: review of src/sh4/assembler-sh4-inl.h

Changes:
- fix function target_address_address()
- updated comments
sh4: activate some tests for snapshots

Re-activate some tests that are working fine with snapshot == on.
Change default timeout time from 60 to 120 secconds
sh4: skip mjsunit tests expected to fail or timeout

Skip tests requiring debugger support.
Skip tests requiring online optimizer.
Skip tests which timeout in debug mode.
sh4: add support for --sim-stack-size option to simulator

Add support for setting stack size for simulator as on arm64.
Add access below stack checks to read/write accesses in simulator.
sh4: review frames-sh4.cc

Changes:
- comments update
sh4: complete review of ic-sh4.cc

Changes:
- fixed some preindex sequences
- updated comments and removed requests for check
sh4: remove some already processed request for check

Remove some comments in code previously reviewed.
sh4: fix local branches that must not record position

The local branches and branches to subroutines, either through
Label or byte offset, must not record the position.
These must be considered code generation private branches and must
not have side effect on the sequence of source positions emitted.
Otherwise the additional recorded position will confuse the actual
source line postitions generated for the input source code.
sh4: complete review of lithium-sh4.cc

Changes:
- comments update
- no fix
sh4: complete review of lithium-codegene-sh4.cc

Note that lithium-codegene-sh4 is not fully implemented as
crankshaft is not activated for sh4 as of now.
Complete review of implemented code in lithium-codegen-sh4.cc/.h
and fix patch smi in full-codegen-sh4.cc.

Changes:
- fix several issues in lithium-codegen-sh4
- comments update
sh4: add comments in autogenerated files

Add comments specifying auto generated files for opcodes and
simulator.
sh4: disable full disassembler in release mode

Disable Linux kernel disassembler code in release node.
This code if GPL and should thus not be compiled as part of
a delivered v8.
The default is thus to activate it only in DEBUG mode.
sh4: fix run-test.py such that simulator is detected in sh4 also

Add sh4 to the list of architectures for which the simulator
and simulator_run flags are detected ans set.
This skips some tests that are skipped when simulator is used.
sh4: skip some tests in webkit testsuite

Add skip of tests that are to slow on sh4 (with no inline cache)
in the webkit testsuite.
sh4: reduce the simulator stack size from 2MB to 512KB

Reduce simulator stack size as setting a too large stack space
cause issues in some tests.
sh4: decrease the number of required threads

This code is a copy of MIPS code.