This change serves to address the following four Github tickets:

    1. ARM64: Optimize pair of "ldr reg, [fp]" to ldp dotnet#35130
    2. ARM64: Optimize pair of "ldr reg, [reg]" to ldp dotnet#35132
    3. ARM64: Optimize pair of "str reg, [reg]" to stp dotnet#35133
    4. ARM64: Optimize pair of "str reg, [fp]" to stp  dotnet#35134

A technique was employed that involved detecting an optimisation
opportunity as instruction sequences were being generated.
The optimised instruction was then generated on top of the previous
instruction, with no second instruction generated. Thus, there were no
changes to instruction group size at “emission time” and no changes to
jump instructions.

consecutive STR and LDR instructions.

during ldr / str optimization.

…struction group boundary.

Change-Id: I074d23c9fed34f713522fe6967cfd1a7007f0e4a
CustomizedGitHooks: yes

Add code to update IP mappings when an instruction is removed.

Various fixes to ldp/stp optimization

…rtMappingKind

Delete unnecessary and incorrect assert

not when chasing an error.

…t or"

This reverts commit 4b0e51e.

"codeGen->genIPmappingUpdateForRemovedInstruction()".

Also, corrected minor bug in instruction numbering
when removing instructions during optimization.

…struction.

…/runtime into LdpStp_Modifications

Change-Id: I58ecdb18c6c89e0f08f114d40a4743e501f0646d
CustomizedGitHooks: yes

Change-Id: Id3c59864e556e19fe05d84a07853c5be0d5aafa5
CustomizedGitHooks: yes