virtual + inheritance example: remove multiple inheritance approach

It was already pretty badly intrusive, but it also appears to make MSVC
segfault.  Rather than investigating and fixing it, it's easier to just
remove it.

example/example-virtual-functions.ref

@@ -14,10 +14,6 @@ VI_AR:
 hihihi
 Unlucky = 99
 
-VI_AMI:
-hihihihihihi
-Unlucky = 990
-
 VI_AT:
 hihihi
 Unlucky = 999
@@ -27,11 +23,6 @@ B says hi 3 times
 Unlucky = 13
 Lucky = 7.00
 
-B_MI:
-B says hi 3 times
-Unlucky = 13
-Lucky = 7.00
-
 B_Tpl:
 B says hi 3 times
 Unlucky = 13
@@ -42,11 +33,6 @@ B says hi 3 times
 Unlucky = 4444
 Lucky = 888.00
 
-C_MI:
-B says hi 3 times
-Unlucky = 4444
-Lucky = 888.00
-
 C_Tpl:
 B says hi 3 times
 Unlucky = 4444
@@ -57,11 +43,6 @@ B says hi 3 times
 Unlucky = 4444
 Lucky = 889.25
 
-VI_CMI:
-B says hi 3 times
-Unlucky = 4444
-Lucky = 1.75
-
 VI_CT:
 B says hi 3 times
 Unlucky = 4444
@@ -72,11 +53,6 @@ B says hi 3 times
 Unlucky = 4444
 Lucky = 8892.50
 
-VI_CCMI:
-B says hi 3 times
-Unlucky = 4444
-Lucky = 175.00
-
 VI_CCT:
 B says hi 3 times
 Unlucky = 4444
@@ -87,11 +63,6 @@ B says hi 3 times
 Unlucky = 4444
 Lucky = 888.00
 
-D_MI:
-B says hi 3 times
-Unlucky = 4444
-Lucky = 888.00
-
 D_Tpl:
 B says hi 3 times
 Unlucky = 4444
@@ -102,11 +73,6 @@ B says hi 3 times
 Unlucky = 123
 Lucky = 42.00
 
-VI_DMI:
-B says hi 3 times
-Unlucky = 1230
-Lucky = -9.50
-
 VI_DT:
 VI_DT says: quack quack quack
 Unlucky = 1234