Auto merge of #62592 - nikic:actually-update-llvm, r=alexcrichton

Update to LLVM 9 trunk

Following the preparatory changes in #62474, this updates the LLVM submodule to https://github.com/rust-lang/llvm-project/tree/rustc/9.0-2019-07-12 and:

 * Changes the LLVM Rust bindings to account for the new SubtargetSubTypeKV.
 * Adjusts a codegen test for the new form of the byval attribute that takes a type.
 * Makes a PGO codegen test more liberal with regard to order and linkage.
 * Builds InstrProfilingPlatformWindows.c as part of libprofiler_builtins.
 * Moves registration of additional passes (in particular sanitizers) to the end of the module pass manager.
 * Disables LLDB on builders.

r? @alexcrichton