Move lld.exe (windows) and add dependent library libwinpthread-1.dll

Move lld.exe to lld-bin directory; add lld-bin/libwinpthread-1.dll; add
trampoline.

Best practice is to ship necessary libraries of expected versions along
with build tools, rather than requiring them to be found elsewhere.

lld.exe depends on libwinpthread-1.dll and windows looks for it in the
same directory as lld.exe.  Unfortunately, there's already a 32-bit
libwinpthread-1.dll at the tool root (used by 32-bit executables at
the tool root), and lld.exe is a 64-bit executable, so it needs its own
directory and its own library.

In the old location of lld.exe, we add a trampoline executable (a build
artifact) in lld-bin; this means Gradle, which invokes lld.exe in the old
location, does not have to change.

Bug: 148267171
Bug: 142590626
Bug: 144040336

Test: (gLinux) m TARGET_PRODUCT=sdk_phone_armv7 TARGET_BUILD_VARIANT=userdebug sdk dist sdk_repo
      (gLinux) m TARGET_PRODUCT=sdk_phone_armv7 TARGET_BUILD_VARIANT=userdebug win_sdk dist sdk_repo

Merged-In: Ice6710ed204a25d09ac596207c02b8b99ca95b8b
Change-Id: Ice6710ed204a25d09ac596207c02b8b99ca95b8b
(cherry picked from commit 24e52959d723c2b47acc170b0d2784379a6e99c2)
2 files changed