TST: Increase some floating point datatypes and tolerances

This is for floating point errors that crept in with
AVX512 instruction sets on some CI architectures.

Author: greglucas

lib/matplotlib/tests/test_axes.py

@@ -3327,7 +3327,9 @@ def test_tick_space_size_0():
 
 @image_comparison(['errorbar_basic', 'errorbar_mixed', 'errorbar_basic'])
 def test_errorbar():
-    x = np.arange(0.1, 4, 0.5)
+    # longdouble due to floating point rounding issues with certain
+    # computer chipsets
+    x = np.arange(0.1, 4, 0.5, dtype=np.longdouble)
     y = np.exp(-x)
 
     yerr = 0.1 + 0.2*np.sqrt(x)

lib/matplotlib/tests/test_streamplot.py

@@ -78,7 +78,7 @@ def test_maxlength():
 
 
 @image_comparison(['streamplot_direction.png'],
-                  remove_text=True, style='mpl20', tol=0.056)
+                  remove_text=True, style='mpl20', tol=0.073)
 def test_direction():
     x, y, U, V = swirl_velocity_field()
     plt.streamplot(x, y, U, V, integration_direction='backward',

lib/mpl_toolkits/tests/test_axisartist_grid_helper_curvelinear.py

@@ -140,7 +140,7 @@ def test_polar_box():
     ax1.grid(True)
 
 
-@image_comparison(['axis_direction.png'], style='default', tol=0.07)
+@image_comparison(['axis_direction.png'], style='default', tol=0.071)
 def test_axis_direction():
     # Remove this line when this test image is regenerated.
     plt.rcParams['text.kerning_factor'] = 6

lib/mpl_toolkits/tests/test_mplot3d.py

@@ -1,6 +1,5 @@
 import functools
 import itertools
-import platform
 
 import pytest
 
@@ -547,7 +546,7 @@ def test_text3d_modification(fig_ref, fig_test):
         ax_ref.text(x, y, z, f'({x}, {y}, {z}), dir={zdir}', zdir=zdir)
 
 
-@mpl3d_image_comparison(['trisurf3d.png'], tol=0.03)
+@mpl3d_image_comparison(['trisurf3d.png'], tol=0.061)
 def test_trisurf3d():
     n_angles = 36
     n_radii = 8
@@ -1369,7 +1368,7 @@ def test_errorbar3d():
 
 
 @image_comparison(['stem3d.png'], style='mpl20',
-                  tol=0.0 if platform.machine() == 'x86_64' else 0.003)
+                  tol=0.003)
 def test_stem3d():
     fig, axs = plt.subplots(2, 3, figsize=(8, 6),
                             constrained_layout=True,