[MIPS] Ensure correct buffer alignment for doubles.

For mips, doubles and objects containing them must be aligned
to 8 bytes. This fixes up the LinearAllocator, so that the
graphics context recording storage is properly aligned.

This fixes a browser startup crash in Recording::draw()
for concatCTM(), as AffineTransform contains an array of
doubles.

Change-Id: I8c06d0f4ed38d6ff0aad06d77016e55d57bb39b9
1 file changed