Bounded copies (memcpy_s / __memcpy_chk) and strtoll/strtod parsing

[ASDAlexander77]

Summary

Two commits:

1. parseInt / parseFloat use strtoll / strtod, not atoi / atof. atoi and atof leave a value out of range undefined. MSVC saturated, while glibc wrapped: parseInt("3000000000") was -1294967296 on Linux. parseInt with a radix called strtol, whose long is 64 bits on Linux and was read there as a 32-bit result. Every parse now goes through strtoll (base 10 unless one is given), and a 32-bit result is clamped to the i32 range, so every target gives the same answer. The strto* functions have no _s variants in the MSVC CRT; they are its recommended replacement for ato*.

2. Copies sized at run time are bounded. String concatenation, string copies and array slices go through LLVMCodeHelperBase::MemoryCopy(dest, destSize, src, count), which ends the process rather than write past the destination:

   • Windows target: the CRT's memcpy_s, whose invalid parameter handler fails fast (0xC0000409)
   • Linux, Android, Darwin: they have no memcpy_s, so they get the fortified __memcpy_chk ("buffer overflow detected"). LLVM turns it back into a plain memcpy where it can prove the copy fits.
   • wasm: llvm.memcpy, as before

   The JIT binds memcpy_s to tslang's own CRT, as it does memcpy. The manifest resource for a Windows executable is copied with memcpy_s on a Windows host.

The DefaultLib side (its own string copies, through a C++ boundedCopy) is ASDAlexander77/TypeScriptCompilerDefaultLib, branch memcpy-s-win32. Merge this one first, or both together.

Test plan

• New 00parse_number_range.ts (compile, JIT, and the rc/none corpus): saturation at both ends, radix, strtod overflow and underflow, casts to i32, i64 and f32. Before the fix, the four out-of-range cases failed on Linux (WSL) and passed on Windows.
• --emit=llvm per target: Windows has 35 memcpy_s calls, Linux and Android have 35 __memcpy_chk calls, wasm has llvm.memcpy
• Windows Release ctest -C Release: 3904/3904
• CI: Linux, where __memcpy_chk is exercised end to end

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