std::dynamic_lib: start fixing windows implementation

The code compiles and runs under windows now, but I couldn't look up any
symbol from the current executable (dlopen(NULL)), and calling looked
up external function handles doesn't seem to work correctly under windows.
Update doc references to new names for std, extra, and std::libc
Reproduce text changes from @brson PR 7176 and fix a typo therein
mk: tests.mk simplify the method to clean arm testing directory
etc: modify adb_run_wrapper.sh to avoid 'expr' unrecognization at some android devices
etc: add TEST_EXEC_ENV for run-pass to adb_run_wrapper.sh
test: adjust some test cases of run-pass for android
std: fix stat struct of android (SEGV error from run-pass/stat.rs on android)
rt: fix jemalloc android cross-compile for mac
Use DIBuilder in debuginfo
Made the while DebugContext mutable, not just created_* hashes
Disabled create_arg
Move "return" basic block after all other function blocks.
Debug loc for local var declarations
Removed extraneous string allocations.
Misc refactoring.
Fixed compile warnings.
Fixed whitespace "errors".
Fixed remaining issues to pass debug-test/* tests.
Made debugger scripts source line insensitive.
Converted vec::map to member.
Made unimplemented debuginfo a note rather than a compiler error.
Refactoring and tidy warnings cleanup.
Fixed rebase fallout .