Transient extrusion demo gets different cell volumes after PETSc update

[jeff-cohere]

In #236 , we updated to PETSc v3.17.3 and observed a change in the output for the transient DM extrusion demo (transient-snes-mpfaof90-dmplex-extrude). From the regression test log:

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transient-snes-mpfaof90-dmplex-extrude...
    cd /home/jeff/projects/pnnl/TDycore/demo/transient
    /home/jeff/projects/pnnl/TDycore/demo/transient/transient_snes_mpfaof90 -ma
    # transient-snes-mpfaof90-dmplex-extrude : run time : 1.20 seconds
    diff transient-snes-mpfaof90-dmplex-extrude.regression.gold transient-snes-
    FAIL: Liquid Pressure:Max : 0.05165348704928539 > 1e-12 [relative]
    FAIL: Liquid Pressure:Min : 0.0012106965185768362 > 1e-12 [relative]
    FAIL: Liquid Pressure:Mean : 0.016393590416747494 > 1e-12 [relative]
    FAIL: Liquid Pressure:0 : 0.0012106967574871913 > 1e-12 [relative]
    FAIL: Liquid Pressure:2 : 0.031121615192353066 > 1e-12 [relative]
    FAIL: Liquid Pressure:4 : 0.010385206661480422 > 1e-12 [relative]
    FAIL: Liquid Pressure:6 : 0.0012106966381568152 > 1e-12 [relative]
    FAIL: Liquid Pressure:8 : 0.03112161384536345 > 1e-12 [relative]
    FAIL: Liquid Pressure:10 : 0.010385206661422118 > 1e-12 [relative]
    FAIL: Liquid Pressure:12 : 0.0035453382620971004 > 1e-12 [relative]
    FAIL: Liquid Pressure:14 : 0.05165348704928539 > 1e-12 [relative]
    FAIL: Liquid Pressure:16 : 0.010385205777137793 > 1e-12 [relative]
    FAIL: Liquid Pressure:18 : 0.001210696637877151 > 1e-12 [relative]
transient-snes-mpfaof90-dmplex-extrude... failed.
----------------------------------------

@bishtgautam wrote:

@knepley For the -dm_plex_extrude_normal being used in the TRANSIENT test, I'm getting differences in cell volume between v3.16.2 and v3.17.2. Is the difference in cell volumes between the two versions of PETSc expected?