libm: optimistic pow calling

Call optimized pow optimistically and revert to full range
implementation if we detect an out-of-range input.

Change-Id: I02657c2a254e9796e795a8fcc6ae43e24c9d37b9
bionic/libm: fix x86 support regression

Support for x86 and MIPS broke due to an incorrect merge conflict
resolution in commit 5015fe9.  Commit d348cd5 repaired MIPS support
but not x86.  This commit repairs the incorrect merge conflict
resolution, bringing back support for x86 (and potential future
architectures).

Change-Id: I8994d653e5a2f79c9bfacb1c87159c8cdd4f81a7
[MIPS] fix bionic libm on MIPS support

the s_sin.c and s_cos.c are needed to be added to compile MIPS libm

Change-Id: I48e2f70cb8fb5a63c6022129c3ca1c2699d058e6
Signed-off-by: Rocky Zhang <zhangyan.hit@gmail.com>
libm: sqrt and sqrtf via ARM vsqrt instruction.

Optimized sqrt and sqrtf for arm by using hardware
opcode for sqrt rather than generic slow portable
code.

Change-Id: I9888d58547bcfca7dfc1400d3e7e222599167249