Port 57168634

Original Commit Message:

    Declare an inline method for the various backends to define based on
    alignment requirements. That way backends that might take a performance
    hit when data is not naturally aligned can specify the requirements.

    With this requirement defined, we can then specify that SIMD values
    require 16 bytes on the stack.

    This also opens up the possibility of storing 32-bit values in 32-bits,
    rather than the fixed kStackSlotSize.

R=zhin@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ic61ba7508d37971a04fddad9e25025d038fdc3bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1994181Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#65706}