Threshold Consistency for ES2 FBO Tests

Threshold Consistency for ES2 FBO Tests

ES3 and 3.1 tests both use the same fuzzycompare threshold value
for their FBO tests, whereas ES2 uses a smaller value despite
having the same coarse formats that require the high threshold.

This change adjusts the ES2 FBO Render Test threshold to match
the value set for ES3 and ES3.1

Affects:

dEQP-GLES2.functional.fbo.render.*

Components: GLES2

VK-GL-CTS Issue: 2715

Change-Id: I15203e1ecf45081ec27baee59b780c5bdf5aacaf
(cherry picked from commit 34d1a2e19b9e12b6413fe61d8dc4ee752c6053e4)